std::shared_ptr<T>::operator bool
Declarations
explicit operator bool() const noexcept;
Checks if *this
stores a non-null
pointer, i.e. whether get() != nullptr
.
Parameters
(none)
Return value
true
if *this
stores a pointer, false
otherwise.
Notes
An empty shared_ptr
(where use_count() == 0
) may store a non-null
pointer accessible by get()
, e.g. if it were created using the aliasing constructor.
Example
#include <iostream>
#include <memory>
void report(std::shared_ptr<int> ptr)
{
if (ptr) {
std::cout
<< "*ptr="
<< *ptr << "\n";
} else {
std::cout
<< "ptr is not a valid pointer.\n";
}
}
int main()
{
std::shared_ptr<int> ptr;
report(ptr);
ptr = std::make_shared<int>(7);
report(ptr);
}
Result
ptr is not a valid pointer.
*ptr=7